UC Berkeley Berkeley Scientific Journal

Title Interview with Joel Fajans

Permalink https://escholarship.org/uc/item/4w0693f3

Journal Berkeley Scientific Journal, 15(2)

ISSN 1097-0967

Authors Gururangan, Kapil Owen, Elaine Ding, David

Publication Date 2011

DOI 10.5070/BS3152011587

Undergraduate

eScholarship.org Powered by the California Digital Library University of California BSJ • 1 2 ssue I • 15 olume • V 2011 • pring S •

couldn’t prove it.” iction F but at the time we just Well, there could be many consequences but there could be many consequences Well, Sure. Our goal is eventually to study the eventually is Sure. Our goal cience caught, back in 2009, were “...what we thought we had What are the consequences of violating CPT? indeed antihydrogen , • S BSJ: found out there was What would happen if you guys some difference between antihydrogen and regular , apart from the charge of those particles? Fajans: the most, the ones were likely to look for look at the color with which antihydrogen glows. You first is to may know that all atoms glow with characteristic see that neon signs. Some of the in time colors. You they’re blue. Some are red. It has to do with the gas that’s inside the signs – this color is characteristic of that something it turns out that it’s and the , with extraordinary precision. can measure scientists In principal, we can measure the color of something, more specifically thewavelength, we’llbut just call the 1 to the 18th. That is to one part in it the color Now, that in and by 18 zeros. of 1 followed precision of itself may not seem that exciting, but one of the reasons for doing this is because it might motivating on of the grand challenges in physics and help answer Fajans: Antihydrogen is a atoms. properties of antihydrogen form of made from an , which and a which charged is a negatively is an antimatter , a positive electron. There’s a substantial called CPT [change, time and theory, that predicts which variance and parity symmetry] aside from these in changes the sign, that hydrogen we’d antihydrogen are absolutely identical and and like to see if that’s really true. If it turns out not to be be would CPT, well true, then the theory of physics, overthrown. ournal J s jan a cientific F S erkeley oel B J with

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Kapil Ding Elaine Owen, David Gururangan, I BSJ: issue, we were really interested in your research you are doing at CERN. Can you tell us the anti at CERN doing what you are for your project goal of Switzerland is right now? Dr. Joel Fajans’ research has recently Dr. Joel Fajans’ research captured headlines at the CERN, ALPHA collaboration as a part of the created and captured antihydrogen Swizerland that named was That event 2010. particles in November by Physics of the Year the #1 Physics Breakthrough and since then, World magazine the team has worked of time, for longer periods to store these anti-atoms clocking 1,000 seconds April in After 2011. getting his Ph.D. from Massachusetts Institute ofTechnology in physics department 1985, Professor Fajans joined the lab has since worked as a faculty member in 1988. His paper on and the occasional on charged plasmas biking. of love to his speaks that motion gyroscopic While in Switzerland, Professor and the future of thoughts on the uses of antihydrogen Fajans shared his antimatter research when Berkeley Scientific Journal 2011. Skype in the summer of spoke with him over in sciences. Mainly, why a more advanced form of further studied the properties of antimatter. I guess it’s hard to say. Right now our goals this year are two- isn’t there more antimatter Schrödinger equations to some extent, its come back to Berkeley since I’m a fold. One, we are trying to start to do physics with in the universe? The theory seemed to him to be quite member of the team, there are many members on the these atoms – start to do the spectroscopy with these of the big bang, which is useful and predictive and team, about 40 people from institutions worldwide. atoms. Second, our other goal is to simply get more of a remarkably successful turned out to be correct We became the first people to trap neutral antimatter. them and make them more easily. It’s still a struggle theory, has a small problem equations. They have a People have managed to trap an antiproton and for us to trap – not to make them, it turns out to be with antimatter because it problem in which it is before. The goal is to keep the trapped in fairly easy to make antihydrogen atoms – but it’s still predicts that there should possible, in fact necessary one place. This isn’t so easy to do because matter and a struggle for us to trap the antihydrogen atoms that have been just as much that his equations would we’ve managed to make. antimatter in the universe blow out, that would be as matter and when you mathematical infinities BSJ: How much anti hydrogen look around us that appears in the problem and he “...if you had a fistful of antimatter you could can you make? Say in a couple not to be so. It appears believed in this theory make a rocket probe that would go to the stars...” days or something. that there’s mostly matter, and he believed in his almost entirely matter for equations, so he invented Fajans: Well in the terms of that in the universe and a way to get rid of those atoms we can make quite a very, very little antimatter mathematical infinities antimatter, when they touch each other, they explode few at the moment. We make about 5,000 antihydrogen and nobody knows why. which was basically to – they blow up. Physicists call this . In atoms. Of course we start with ingredients, positrons

This actually has a name – pretend that there were fact, when antimatter touches matter, all of the and , about every 15 minutes when we BSJ it’s called the baryogenesis positive in the in the matter and the antimatter gets converted into have beam. I will come to that in a second. We can problem – and its one of world and amazingly energy, via Einstein’s famous equation E = mc2, which make about 5,000 anti hydrogen atoms. But even on the outstanding critical enough this purely predicts the amount of energy that you get out of all of our best days, we only manage to keep one of those BSJ problems in physics is to try hypothetical prediction this mass. If you want to keep antimatter around, you atoms around, so we lose 4,999 and we keep one of and explain that. Well, even was quickly found to have to make a bottle with no sides. You can’t simply them entrapped. Our experiment runs 24 hours a though the connections are be correct by a physicist put it into, say a glass bottle, because as soon as the day, but there are other experiments with which we sort of subtle, if it turned named Carl Anderson, antimatter hit the sides they will annihilate and that share the antiprotons for, and so we run effectively out that antihydrogen was who detected positrons would be the end of it. So you have to make a bottle 8 hours of a day and with that we can, at 4 different from hydrogen, in the early 1930’s. that has no sides and the way physicists do this is to times an hour, make 20,000 atoms an hour if things are and glowed a different That’s where it stood use magnetic and electric fields. But it turned out to running well. And we’ve got 8 hours, so that is 160,000 color; this might explain for a while, but then be particularly tricky for antihydrogen atoms. What antihydrogen atoms an hour or something like that. this rather fundamental people started to wonder we succeeded in doing last year was to finally manage 160,000 antihydrogen atoms a day, but we will only mystery of how it came to whether or not there were to build a bottle that would contain some be here. antiprotons, protons that antihydrogen atoms. were negatively charged. BSJ: In terms of the actual At the time the biggest BSJ: Yes, so we read the paper that you guys “160,000 antihydrogen atoms a day, history of this field, I accelerator in the world wrote regarding you trapped it for, I believe, understand that Berkeley is was in Berkeley partially 1,000 seconds? but we will only trap a few of them.” featured quite heavily in the to answer this question. development of anti matter The building in which Fajans: Right. and I think there have been it was built was just a couple noble laureates recently torn down. Up BSJ: And that’s enough time to perform the associated with it. Can you until last year you could spectroscopy and other experiments? trap a few of them. walk us through how this go up into the Berkeley BSJ: So you mentioned beam? field has been developed lab and you could see Fajans: Yeah, 1,000 seconds in physics terms is forever. over time and sort of how the building and the It’s sort of boring actually. We had a joke that we could Fajans: Yes, these experiments have to be done at we’ve lead up to this sort Figure 1. Above a few of components of the ALPHA remains of the accelerator put an atom into a trap and then go out for coffee and CERN because, while there are other sources of of culmination project you apparatus, which is designed to trap antihydrogen. there called the Bevatron. then see if was still there when we came back. antiprotons in the world, CERN is the only source of guys are doing? And the Bevatron had slow antiprotons. You need an accelerator complex to several competing experiments that were looking for BSJ: So have you guys done the spectroscopy? make antiprotons. Antiprotons are made intrinsically Fajans: Well, sure, antimatter was first predicted to antimatter and two of the people there, Segrè and with a great deal of energy, but we need the antiprotons exist in a series of vapors in 1930 by a theorist named Chamberlain, lead a team of about 5 people in which Fajans: No. That’s still some years off. We’re trying to have very, very little energy, so in fact, most of our Dirac and it was an amazing feet of imagination on they discovered the, well they were the first to discover to do some spectroscopy this year, but it will be experimental effort has been extracting energy from his part basically he had set up equations which the anti proton. So that’s how that came about. relatively crude. It’s probably 5-10 years before we can these antiprotons. At most accelerator complexes, were a more advanced form of quantum mechanics The story basically leaves Berkeley for a while and do precision spectroscopy. Maybe less, maybe more – they simply start out with too much energy for us goes to places like and CERN where people 2 • Berkeley Scientific Journal • Science Fiction • Volume 15 • Issue 2 Berkeley Scientific Journal • Science Fiction • Volume 15 • Issue 2 • 3 BSJ • 5 2 ssue I • 15 olume • V 2011• pring S •

iction F Well Well actually I am an oddity at CERN; I am cience So you mentioned gyroscopes earlier and we were were earlier and we So you mentioned gyroscopes • S thinking about it, and eventually came up with this thinking about it, and eventually proposal for this modification to thethat thing of ideasort one the think, I But recounting. were that they marked my entire life, is that I have always liked to build things and make them work. Like when you I was, thing exciting most the what about talking were designing things, building work, to things getting like new and fun things, and that has been what most of I have done in physics: building perfecting them, and getting them to work and that is experiments, and when you get your job day-to-day satisfaction. Not in in a lifetime, these brand new things that happen once in unless you really believe, couple years, or every which case they happen frequently, but that is not the point of my situation. BSJ: Fajans: Fajans: it though physicist, plasma the only not probably in to get involved way common is not a very certainly CERN. In the field of plasma physics most physicists work on fusion actually, energy, I have always been in one obscure corner of I have plasma physics, never and I kind of almost drifted into this done that and conference a to went I because accident by almost going to talking about how they were heard someone telling me and what they were trap an antihydrogen just didn’t make sense to me. So that is when I started ournal J cientific S erkeley B Figure 2. An external 2. An view of the ALPHA apparatus. Figure And that’s great. And when the page paper in And that’s great. So were you ever interested in science fiction as Yeah, of course. BSJ: Yeah, Fajans: all gathered in our control room Nature came out, we the Nature website, up on it show watched we and news stories about it started watching and then we deal great a was It publicity. of lot a was there because only, moments of sorts those for fun, but if you live of then your life is going to be pretty sparse. BSJ: a kid? What got you interested in the fields of physics studying before that you study now or that you were you joined CERN? moment when that particular antihydrogen atom was was atom antihydrogen that particular when moment and Nick, Will had that after named So we person. operating, II. I think for one of them I was maybe Will so temporarily one was named after me. not as long it’s so for been going on has this neat, but It’s pretty succeeds in which it suddenly some moment if there’s that don’t realize it’s comes together. and it all You after it has because for a while even all come together things are still uncertain. Well, I’ve been working on to have really fun it’s and long time great, a a for this it work. 2 ssue I • Well that’s sort of similar to what we do, we what to similar of sort that’s Well Not to sound facetious, but you know, it’s not Not to sound (laughs) When something catches fire. (laughs) When something catches 15 olume Yeah, yeah. I have. yeah. Yeah, BSJ: Fajans: but it’s a lot harder to do it. Antihydrogen is a small Antihydrogen it. lot harder to do but it’s a magnet. It is like a tiny, tiny bar magnet – incredibly – weak but nonetheless it has a little bit of magnetism in it. We create a specially designed of into the center antihydrogen forces that basically magnetic field design of the magnet we special magnet. The this very proposals Berkeley lab. There were use came from my took the standard but we systems other mechanic for actually is which somewhat, it modified and proposal standard the that think didn’t I field. this into got I how configuration would workvery well and proposed a modification to it, andwe tested it in Berkeley. There undergraduate a Berkeley that worked on this was with me in terms of proposing this modification and to show the other did experiments, in Berkeley, we standard configuration indeed had problems. So it’s a complicated magnet and it’s really quite similar to seen. that floating magnet idea that you’ve the research of the progress of terms in Right. So BSJ: exciting moment that so far, what has been the most been a part of so far at CERN? you’ve Fajans: fire? BSJ: (laughs) How often do things catch Fajans: hadn’t caught one moment where we as if there was had another where we antihydrogen and there was beginning, in 2009 for instance, we because in the very it turns out 6 antihydrogen had caught, as thought we That doesn’t sound the course of the year. atoms, over like much does it? We thought we had caught them, it and it’s only in 2010 that we couldn’t prove but we had actually that we the techniques to prove developed And had actually caught antihydrogen. that we prove thought we it turned out, in retrospect, that what we indeed antihydrogen had caught, back in 2009, were it. So, for just couldn’t prove atoms, but at the time we the person 15, or 10 or 5 only had we when while, a who happened to be operating the experiment at the • V 2011• things that happen once in a lifetime.” “...that is when you get your job day-to- pring day satisfaction. Not in these brand new S •

iction F cience • S ournal J them to work ...” cientific S erkeley “...most of what I have done in physics: building experiments, B

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4 • Fajans: And perhaps you’ve seen these toys. There’s a seen you’ve And perhaps Fajans: pretty neat toy in which you take sort of a gyroscope, another which has got a magnet in it and spin it over magnets in it, magnet, a stationary base that has some you seen this toy? and it floats in the air. Have BSJ: Right. Fajans: Well you can’t use a electric Fajans: Well fields to trapby pushed it won’t be it is neutral, so antihydrogen because electrons fields, but magnetic we fields.can still use You certainlypoles the two south take, say you that if know of a magnet together they will repel each other. So after you have made cold antihydrogen, what cold made have after you So BSJ: has built? I mean is the setup of the trap that the team on magnetic and electric if it is not heavily focused fields to trap charged particles, how exactly do you trap neutral antihydrogen. student. He is in charge for the evening for us. student. He is in charge for the evening to be able to trap and successfully, but CERN has a CERN but successfully, trap and able to to be accelerator is an of course, CERN, facility. special very at CERN actually but one of the accelerators facility, works backwards. It’s a decelerator, and it takes the that antiprotons all this created with are made and energy and slows them down significantly, reducing that At factor of a thousand. by about a the energy because otherwise we can deal with them, point we to. For instance, Fermilab, which wouldn’t be able than antiprotons actually makes more in Chicago, is much more energetic and CERN does, but they’re we couldn’t use them. I had a shift earlier today that didn’t use antiprotons, so I am home for the evening, working and is collaboration our moment, but at this we are trying to improve our traffic. at the moment is a guy named is running the shift The guy who Berkeley graduate a former Bertsche, and he’s William BSJ BSJ • 7 2 ssue I • 15 olume • V 2011 • pring S •

iction F Yeah it’s really nothing; you really need to it’s really nothing; Yeah None, which is why I am surprised to hear cience A lot of the literature on the ALPHA collaboration collaboration ALPHA of the literature A lot on the • S BSJ: BSJ: for the future sort of some postulating is website kind of energy. What mentioning is it and project, energy an as have antimatter does potential theoretical source? Fajans: unless website, the that on mentions you say that it The problem with it dismissively. it would mention using antimatter as incredibly an energy source inefficient isto make. never out than you put in, you don’t get more energy that First it is you certainly would, but on top of that it is incredibly inefficient to make antimatter. Which, somein ways,because if you is a shame had a fistful of antimatter that would go to the stars quickly make a rocket probe you could but there science, be really fantastic for would which is no prospect whatsoever of me making a fistful of People calculated have – andantimatter. some people get number and other people get one another number – that to make a macroscopic quantity of antimatter, say a gram of antimatter, all all of the transportation, all the computers, production, of the world’s energy all of the eating that and food growing, all of energy would have to be funneled into people would amount of time that various for some making antimatter say is a thousand years up to an interesting thing, in the history of antihydrogen a million years. It is perhaps two hundred million, experiments, a hundred which made, been have antihydrogen atoms million, doesn’t it? sounds like an enormous quantity, a lot but it’s not. it sounds like BSJ: Yeah Fajans: before you atoms make a billion billion antihydrogen a macroscopic quantity of this stuff. have BSJ: I see, so I think that let questions you I go had, to and sleep I’ll now, since is pretty much all of the there, but thank you so much for it’s a bit late over letting me do this interview. Images courtesy of the Alpha http://alpha-new.web.cern.ch/gallery experiment website: ournal J cientific S erkeley B I think what originally got me excited about So what actually was your driving force for So what actually was theory, the CPT theory. Laws like this are overturned are overturned like this Laws theory. the CPT theory, trying of searching, this tradition have physicists and that these laws else is wrong, that everybody to prove are incorrect. It is a fruitful very thing in physics over almost always face the fact that One has to the years. earlier saying was I why is that so correct, are laws the of personal point my from satisfaction is, a lot of the work. to experiment difficult very a get to trying view, It would be foolish of me to think that CPT is wrong; a chance. happen, but there is always it is unlikely to a gravity, Just like you mentioned there is always but nobody up, fall antihydrogen will that chance interacts with measured how antihydrogen has ever gravity with interacts it that unlikely very is It gravity. differentlyway from that the hydrogen interacts with gravity, but maybe it is antigravity. maybe it does, asked me You earlier if I read science fiction, Iwasn’t amount fair a read did I but fan, fiction science huge a when I was a kid. For some reason one of the books that always struck me, I don’t know why, but it was only one I remember in the Tom Swift stories. It is the because it is the only now, and it is somewhat ironic one that is relevant to me now. I think it true it is was Well, Antigravity Paint.” called the Swift and “Tom that if you used antimatter paint, your house would is kind of amusing. blow up rather than rise, but it So I was never really a Star Trek fan. I have of course course of then, and and now Star Trek every seen antimatter torpedoes, and all thatdriving influence force. is really not my BSJ: getting into plasma physics? Fajans: you as is, energy. Fusion fusion was physics plasma know, the promise of the infinite sourcewith essentially no pollution cost. No downside, of energy, that people haven’t downside the major except for get they may never And managed to get it to work yet. to get it to it to work because it is absurdly complicated that’s think I so plant, power a or laboratory a in work what first interested me. But I got sidetracked almost laser- type of a working on started and immediately laser electron free a called is It beam. electron on based and that is what I did my thesis on. And a make to post-doc a as up signed I again, then sidetracked I got succeeded never crystal out of electrons only, and we did some other rather interesting things at that but we did I what is That electrons. of collection this that, with distracted got I until Berkeley, at career my of most for with the antimatter research and started doingprincipally. that 2 ssue I • Well, Well, I think it depends on whether or not We will come back in just two weeks or so. or two weeks just back in will come We That is correct 15 You will be back teaching at Berkeley in the fall will be back teaching at Berkeley You Are you going to move everyone back, or is your back, everyone move Are you going to Cool, so what do you see as the future for antimatter for future the as see you do what so Cool, olume that the in underground is buried out countryside are we here, and is my family summer, And this here. which renting of Prévessin, in the French town a place You complex. the accelerator of right in the middle sits you but if buried, just it is because course, tell, of can’t ring this giant of are signs to look there know where all around in this area, and almost we’re pretty close to the center I think. BSJ: 8B? Physics correct? Teaching Fajans: BSJ: here. family going to stay Fajans: for the semester to start Waiting BSJ: the done have you after but step, one is This research? spectroscopy and the gravity experiments, where do in the future? you sort of see this research going Fajans: will be studying People an interest in the fact. see we this for a very long time. If nothing shows then, up, it well will be an honorable attempt. Physics is full There are of this sort of experiments, by the way. in that people are lots of laws that people believe testing with greater and greater precision, and this is a part of physics. laws are wrong, but when they are wrong, that can It rarely turns out that about a particular thinking revolutionize people’s these field in physics or sometimes physics in general. For that which predicts instance, there is theory call CPT, CPT be the same. hydrogen and antihydrogen should stands for different symmetry, C stands parity, which called that is something for stands P for charge, for time, and it is a stands and T is like handedness, these properties. all of of theory about the symmetry the CP there was theorem, CPT the there was Before in. but it turned out believed theorem that everyone to be true most of the time, but there turned out to be exceptions. That is why people came up with a better • V 2011 • pring S •

iction F that everybodythat else is wrong...” cience • S ournal J cientific S “...physicists have this tradition of searching, trying to prove trying prove to of searching, tradition this have “...physicists Yes, Yes, that is true too. In fact I am sitting here Well, except for the current exchange rate of Well, Well, I think, it is a complicated thing. We Yeah and CERN is probably one of the nicer Yeah That is great, so another thing we were interested interested were another thing we That is great, so erkeley B

6 • Fajans: BSJ: places for a retired physicist to be. pretty pretty, a is it place; lovely a is it frank, Swiss the is good, and the work at CERN, if area. The weather a physicist is really quite exciting. For instance, you’re straddles CERN know. you town, small a in living am I border, and most of the accelerator Geneva the Swiss is actually in France, most of the actual physical There is a tunnel that is like 17 miles around hardware. limited amount of time and are employed at CERN are employed and time amount of limited a couple have We for a fairly limited amount of time. to be because they want of retired physicists hat come with a fun experiment, and they spend 3 or involved here and maybe another month back home. 4 weeks Most of these retired folks are in Canada, and they spend some time at home thinking about our project. physics so much that they can’t quite But they love really retire. Fajans: Fajans: in bike clothes because I am biking home from work. But yeah, I do physics, I spend time with my family, I ride bikes. Berkeley is a great place to ride here. fun coming it is a great place to, so but CERN is a bike, BSJ: together at a large team works such how about was 40 or 50 scientists. have CERN. You planning a had We in meetings. time lot of a spend talking were in which we meeting this afternoon were we and next year, our device about rebuilding going it’s how about details fiddly some about talking you know, talking out ideas, to be constructed. People, than better being idea one about other each with argue the other. In this group there’s about 45 collaborators, this, there are other about 10 of us spend full time on and small on very people who just come and work specific aspects of the experiment, some of which are quite critical to our success, but they only spend a reading through a couple of your catalog of papers of papers catalog your of a couple through reading it students about of your some to after talking and don’t you? riding bikes, that you really like appears BSJ